Novel Applications of Hot-Melt Extrusion Technology
Hot-melt extrusion, an adaptable technology, has established its position in a wide spectrum of manufacturing operations like amorphous solid dispersions, immediate and controlled oral formulations, implants, and taste masked products. In recent years the industrial focus has shifted towards continuous manufacturing, thus melt extrusion is being explored for new applications. The aim of this research work was to investigate the novel applications of hot-melt extrusion by carrying out an in depth study to understand the interplay between the process and the product. The conventional techniques used for the preparation of ointments and nanostructured lipid carriers are multi-step and time consuming batch processes with low productivity. The low mixing efficiency coupled with high batch to batch variability makes these methods less industrial friendly. After optimization of screw configuration and process parameters, these formulations were successfully prepared using melt extrusion in a continuous fashion. The extruded ointment was similar to the conventionally prepared ointment with respect to flow characteristics, texture properties, and drug release profile, demonstrating the potential of hot-melt extrusion in preparation of topical semisolids. In an another study, extruded lidocaine loaded nanostructured lipid carriers were found to be stable for up to 60 days and the drug permeation from the carrier loaded gels was sustained as compared to control, thereby showing promising results for pain management in wounds. In addition, investigating the impact of formulation composition on the product characteristics is of prime importance to understand melt extrusion process. With this goal, a response surface methodology was utilized to study influence of formulation variables on the extruded mucoadhesive films. It was observed that each independent variable influenced one or the other film characteristics either alone or in combination. It is only after such analysis that an optimized system with desired quality attributes could be formulated. The relationship between the process and formulation was elucidated and melt extrusion was found to be a viable approach for preparation of mucoadhesive films. In summary, these successes associated/coupled with the versatility of HME, defines the future potential for this paradigm-changing technology.
continuous manufacturing, films, hot-melt extrusion, nanocarriers, novel applications, topical semisolids, Pharmacy and Pharmaceutical Sciences
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